CN114487865A

CN114487865A - Battery SOC estimation method, battery management system and computer readable storage medium

Info

Publication number: CN114487865A
Application number: CN202011172369.2A
Authority: CN
Inventors: 尹韶文; 林培锦; 尹雪芹
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2020-10-28
Filing date: 2020-10-28
Publication date: 2022-05-13

Abstract

The invention discloses a battery SOC estimation method, a battery management system and a computer readable storage medium. The method comprises the following steps: acquiring actual measurement data of the battery, wherein the actual measurement data of the battery comprises: acquiring actually measured data of the battery, wherein the actually measured data of the battery comprises actually measured current, actually measured voltage, actually measured SOC and actually measured accumulated historical electric quantity; inquiring a correction data table according to the actually measured current and the actually measured voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage; determining an SOC upper limit threshold and an SOC lower limit threshold according to the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data; and correcting the actual measurement SOC by adopting an SOC upper limit threshold and an SOC lower limit threshold to obtain the target SOC. The target SOC estimated by the battery SOC method is high in accuracy and small in error with the actual SOC of the battery, so that the requirements of high accuracy, low resource requirement and high instantaneity can be met for SOC estimation.

Description

Battery SOC estimation method, battery management system and computer readable storage medium

Technical Field

The present invention relates to the field of battery management technologies, and in particular, to a battery SOC estimation method, a battery management system, and a computer-readable storage medium.

Background

SOC (State Of Charge, or remaining Charge) is the ratio Of the remaining dischargeable Charge to the full Charge Of the battery after the battery is used for a period Of time or left unused for a long time. The SOC is an important parameter of the whole battery energy storage system, reasonable utilization of battery energy can be realized by accurately estimating the SOC, and the problem of unreasonable use of over-charge or over-discharge of the battery and the like is prevented, so that the service life of the battery is prolonged.

Existing SOC estimation methods include, but are not limited to, ampere-hour integration, real-time voltage correction, open circuit voltage, and neural network methods, each having its own advantages and disadvantages. The ampere-hour integration method realizes SOC estimation according to current accumulation, is simple to operate and has low resource requirement, but depends on the precision of sampling current, has large requirement on calibration of high pressure during full charge and low pressure during emptying, and has lower accuracy. The real-time voltage correction method is to estimate the SOC according to real-time voltage, real-time current and known charging and discharging voltage curves of each current, the SOC can be accurately estimated when the voltage change is obvious or the use frequency of the battery is high, the error is small, but the SOC estimation accuracy is low and the error is large under the condition that the voltage change is not obvious or the use frequency of the battery is low. The open-circuit voltage method is to measure the battery after the battery is not charged and discharged for several hours when the battery is in a standing state, and to estimate the SOC by using an open-circuit voltage curve. The neural network method is characterized in that the neural network is adopted to correct and accumulate battery data acquired under different operating conditions so as to carry out SOC estimation, and has the advantages of higher accuracy, high resource requirement and high operating condition data requirement.

Disclosure of Invention

The embodiment of the invention provides a battery SOC estimation method, a battery management system and a computer readable storage medium, which aim to solve the problem that the existing SOC estimation method cannot give consideration to high accuracy, low running resources and strong instantaneity.

The embodiment of the invention provides a battery SOC estimation method, which comprises the following steps:

acquiring actually measured data of the battery, wherein the actually measured data of the battery comprises actually measured current, actually measured voltage, actually measured SOC and actually measured accumulated historical electric quantity;

inquiring a correction data table according to the actually measured current and the actually measured voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage;

determining an SOC upper limit threshold and an SOC lower limit threshold according to the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data;

and correcting the actual measurement SOC by adopting the SOC upper limit threshold and the SOC lower limit threshold to obtain a target SOC.

Preferably, the querying a correction data table according to the measured current and the measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data matched with the measured current and the measured voltage includes:

inquiring a correction data table based on the measured current to acquire SOC (system on chip) to-be-selected correction data of which the preset current is matched with the measured current in the correction data table;

acquiring SOC upper limit correction data and SOC lower limit correction data based on the measured voltage and the SOC to-be-selected correction data;

the SOC candidate correction data comprises: the method comprises the steps of presetting current, presetting voltage, presetting SOC and presetting accumulated historical electric quantity.

Preferably, the querying a correction data table based on the measured current to obtain SOC candidate correction data in which a preset current in the correction data table matches the measured current includes:

if the preset current in the correction data table is equal to the actually measured current, taking first correction data corresponding to the preset current as SOC (system on chip) to-be-selected correction data;

if the preset current in the correction data table is not equal to the actual measurement current, second correction data and third correction data in the correction data table are obtained, SOC (system on chip) correction data to be selected are obtained based on the actual measurement current, the second correction data and the third correction data, wherein the preset current in the second correction data is smaller than the actual measurement current, and the preset current in the third correction data is larger than the actual measurement current.

Preferably, the obtaining SOC candidate correction data based on the measured current, the second correction data, and the third correction data includes:

processing the measured current, the second correction data and the third correction data by adopting a data estimation formula to obtain SOC (state of charge) correction data to be selected;

the data estimation formula is ST ═ (Sa-Sb) × (IT-Ib)/(Ia-Ib) + Sb; if Sa is a preset voltage in the second correction data and Sb is a preset voltage in the third correction data, ST is a preset voltage in the SOC correction data to be selected; if Sa is a preset SOC in the second correction data and Sb is a preset SOC in the third correction data, ST is a preset SOC in the SOC to-be-selected correction data; if Sa is preset accumulated historical electric quantity in the second correction data and Sb is preset accumulated historical electric quantity in the third correction data, ST is preset accumulated historical electric quantity in the SOC to-be-selected correction data; IT is measured current; ia is a preset current in the second correction data; ib is the predetermined current in the third correction data.

Preferably, the acquiring the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC candidate correction data includes:

if the preset voltage in the SOC to-be-selected correction data is larger than the actually-measured voltage, determining the difference value between the preset voltage and the actually-measured voltage in the SOC to-be-selected correction data as a first difference value, and determining the SOC to-be-selected correction data with the minimum first difference value as SOC upper limit correction data;

and if the preset voltage in the SOC to-be-selected correction data is smaller than the actual measurement voltage, determining the difference value between the actual measurement voltage and the preset voltage in the SOC to-be-selected correction data as a second difference value, and determining the SOC to-be-selected correction data with the minimum second difference value as SOC lower limit correction data.

Preferably, the determining an SOC upper limit threshold and an SOC lower limit threshold according to the actually measured accumulated historical power amount, the SOC upper limit correction data, and the SOC lower limit correction data includes:

acquiring an upper limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC upper limit correction data, and determining a sum value of a preset SOC in the SOC upper limit correction data and the upper limit error value as an SOC upper limit threshold;

and acquiring a lower limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC lower limit correction data, and determining a difference value between a preset SOC in the SOC lower limit correction data and the lower limit error value as an SOC lower limit threshold.

Preferably, the correcting the measured SOC by using the SOC upper threshold and the SOC lower threshold to obtain the target SOC includes:

if the actual measurement SOC is larger than the SOC upper limit threshold value, determining a preset SOC in the SOC upper limit correction data as the target SOC;

if the actual measurement SOC is smaller than the SOC lower limit threshold, determining a preset SOC in the SOC lower limit correction data as the target SOC;

and if the actual measurement SOC is not smaller than the SOC lower limit threshold value and the actual measurement SOC is not larger than the SOC upper limit threshold value, determining the actual measurement SOC as the target SOC.

Preferably, the measured battery data further includes a measured accumulated current error;

after the acquiring the measured battery data, the method for estimating the SOC of the battery further includes:

comparing the actually measured accumulated current error with a current error tolerance value;

if the actually measured accumulated current error is larger than the current error tolerance value, executing the query correction data table according to the actually measured current and the actually measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage;

and if the actually measured accumulated current error is not larger than the current error tolerance value, updating the configuration correction data in the correction data table based on the actually measured battery data.

Preferably, the updating the configuration correction data in the correction data table based on the battery measured data includes:

acquiring SOC primary selection correction data of which all the preset SOCs are matched with the actually measured SOCs in the correction data table, determining the SOC primary selection correction data of which the preset current is adjacent to the actually measured current as first to-be-updated correction data and second to-be-updated correction data, and determining the first to-be-updated correction data and the second to-be-updated correction data as SOC to-be-updated correction data, wherein the preset current in the first to-be-updated correction data is smaller than the actually measured current, and the preset current in the second to-be-updated correction data is larger than the actually measured current;

processing the battery measured data and the SOC to-be-updated correction data to obtain a measured unreliable value corresponding to the battery measured data and an updated unreliable value corresponding to the SOC to-be-updated correction data;

and if the unreliable value to be updated is empty or the actually measured unreliable value is smaller than the unreliable value to be updated, updating the corrected data to be updated of the SOC by adopting the actually measured data of the battery.

Preferably, the processing the actually measured battery data and the corrected SOC data to be updated to obtain an actually measured unreliable value corresponding to the actually measured battery data and an unreliable value to be updated corresponding to the corrected SOC data to be updated includes:

calculating the actually measured data of the battery by adopting an actually measured unreliable value formula QT (CTBm) ═ ABS (IT-CTBm) × f + DT × g + (CT-CT) × h, and acquiring an actually measured unreliable value corresponding to the actually measured data of the battery;

calculating the corrected data to be updated of the SOC and the actually measured data of the battery by adopting an unreliable value formula Qn (CTBm) ═ ABS (In-CTBm) × f + Dn × g + (CT-Cn) × h to obtain an unreliable value to be updated corresponding to the corrected data to be updated of the SOC;

wherein qt (ctbm) is an actually measured unreliable value corresponding to the actually measured data of the battery; CTBm is a preset current; ABS is an absolute value function; IT, DT and CT are respectively the measured current, the measured accumulated current error and the measured accumulated historical electric quantity in the measured data of the battery; qn (CTBm) is an unreliable value to be updated corresponding to the correction data to be updated of the SOC; in, Dn and Cn are respectively a preset current, a preset accumulated current error and a preset accumulated historical electric quantity corresponding to the corrected data to be updated of the SOC; f is the current coefficient; g is an accumulated current error coefficient; h is the accumulated historical electric quantity coefficient.

The embodiment of the invention also provides a battery management system, which comprises a memory, a processor and a computer program which is stored in the memory and can run on the processor, wherein the processor realizes the battery SOC estimation method when executing the computer program.

An embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored, and when the computer program is executed by a processor, the method for estimating the SOC of the battery is implemented.

According to the battery SOC estimation method, the battery management system and the computer readable storage medium, the correction data table is inquired according to the measured current and the measured voltage, and the SOC upper limit correction data and the SOC lower limit correction data are quickly determined, so that the SOC estimation requires low resources and is beneficial to providing the real-time property of SOC estimation; and determining an SOC upper limit threshold and an SOC lower limit threshold based on the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data, and correcting the actually measured SOC by utilizing the SOC upper limit threshold and the SOC lower limit threshold for evaluation, so that the accuracy of the output target SOC is higher, the error between the output target SOC and the actual SOC of the battery is small, and the requirements of high accuracy, low resource requirement and high instantaneity can be considered for SOC estimation.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.

FIG. 1 is a flow chart of a method of estimating battery SOC according to an embodiment of the present invention;

FIG. 2 is another flow chart of a method for estimating battery SOC according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The BATTERY SOC estimation method provided by the embodiment of the invention can be applied to a BATTERY management system (BATTERY MANAGEMENT SYSTEM, BMS for short) which is connected with the BATTERY and used for estimating the SOC of the BATTERY, so that the estimated target SOC has the advantages of high accuracy, low resource requirement, high real-time property and the like.

In this embodiment, the memory of the BMS stores a correction data table in advance, and the correction data table is a data table in which different configuration correction data are recorded in advance. The configuration correction data refers to data which is formed according to the battery operation condition before the system time for acquiring the measured data of the battery and is recorded in the memory of the BMS, and can be understood as data which is required to be called for estimating and correcting the measured SOC.

Since the BMS has limited storage resources, the configuration correction data in the correction data table is limited, and X × Y configuration correction data can be stored in the correction data table according to the storage resources provided by the BMS, where X is the number of the preset SOC, for example, if the values of the preset SOC are 5%, 15%, 25%, 75%, 85%, and 95%, X is 6; and Y is the number of the preset current, if the value of the preset current is 0.2C, 0.5C, 0.9C, 1C and 2.2C, Y is 5, and 30 configuration correction data are stored in the correction data table.

As an example, according to test data formed during the test operation of the battery, a voltage-current actual measurement curve corresponding to X preset SOCs is drawn in advance, and then Y preset currents are determined according to a current sampling rule, so that the preset voltage is determined according to the preset currents and the voltage-current actual measurement curve. In this example, the Y preset currents may be determined by an arithmetic operation rule of arithmetic operation to reduce the difference to the maximum extent, so as to help reduce the error of the subsequent SOC estimation, where the Y preset currents are preset currents CTBm, where 1 ≦ m ≦ Y; as described above, the predetermined current CTB1 ═ 0.2, CTB2 ═ 0.7, CTB3 ═ 1.2, CTB4 ═ 1.7, and CTB5 ═ 2.2.

In this example, the configuration correction data includes a preset current, a preset voltage, a preset SOC, a preset accumulated current error and a preset accumulated historical power, and [ SOCn, In, Vn, Dn, Cn ] may be used to represent nth configuration correction data, where 1 ≦ n ≦ X Y. The preset SOC is a preconfigured SOC of the battery that may require correction, which may be indicated as SOCn. The preset current is a preset current In the battery working process which may need to be corrected, and may be represented by In, specifically, a charging current or a discharging current. The preset voltage is the voltage which is formed and recorded before the system time of receiving the measured data of the battery and is required for realizing SOC estimation correction, and can be represented by Vn. The preset accumulated current error is the accumulation of all error currents before the system time of receiving the measured data of the battery and can be represented by Dn. The preset accumulated historical electric quantity refers to the accumulation of all electric quantities before the system time of receiving the actually measured data of the battery and can be represented by Cn. For example, when the SOC estimation is performed by the real-time voltage correction method, the predetermined SOC, the predetermined current, and the predetermined voltage are specific sampling points in known charging/discharging voltage curves of each current.

In one embodiment, as shown in fig. 1, a method for estimating SOC of a battery is provided, which is described by taking the method as an example in a BMS, and comprises the following steps:

s11: and acquiring actually measured data of the battery, wherein the actually measured data of the battery comprises actually measured current, actually measured voltage, actually measured SOC and actually measured accumulated historical electric quantity.

The battery actual measurement data refers to data related to the battery, which is acquired by the BMS in real time. The measured current is the current of the battery working process acquired by the BMS and can be I_TThe representation can be understood as the current determined when the SOC algorithm method is adopted for processing, specifically, the charging current can be adopted, and the discharging current can also be adoptedAnd (4) streaming. The measured voltage is the voltage obtained by BMS in real time in the working process of the battery, and can be V_TThe representation can be understood as the voltage determined when processing is performed using the SOC algorithm method. The measured SOC is the SOC of the battery obtained by the BMS in real time, and the available SOC_TBy representation, it is understood an estimated SOC determined using an SOC estimation method. The actual measurement accumulated historical electric quantity is the accumulation of all the electric quantities counted after the actual measurement data of the battery is received, and C can be used_TAnd (4) showing. For example, in the process of charging the battery, the actually measured accumulated historical electric quantity is the accumulation of all the charged electric quantities; during the discharging process of the battery, the actually measured accumulated historical electric quantity is the accumulation of all discharging electric quantities. It can be understood that the measured accumulated historical electric quantity includes all accumulated historical electric quantities before the system time and the accumulation of the electric quantity in the current measured data of the battery.

As an example, the BMS obtains the measured data of the battery in real time, the measured data of the battery comprises the measured current, the measured voltage, the measured SOC, the measured accumulated current error and the measured accumulated historical electric quantity, and the SOC can be used_T、I_T、V_T、D_T、C_T]Representing measured data of the battery. For example, during the charging process of the battery, when the measured current is charged to the measured voltage V0 by using the measured current of 1.2C, the SOC estimation is performed on the measured current of 1.2C and the measured voltage V0 by using the real-time voltage correction method to obtain the measured SOC0, the measured accumulated current error D0 and the measured accumulated historical electric quantity C0 are calculated by combining the configuration correction data, and the measured data of the battery [ SOC0, 1.2C, V0, D0, C0] are obtained]。

S12: and inquiring a correction data table according to the actually measured current and the actually measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage.

When the real-time voltage correction method is adopted for SOC estimation, when the SOC is in the middle section (such as 30% -70%), the SOC estimation accuracy is higher, and the error between the estimated actual measurement SOC and the actual SOC of the battery is smaller; when the SOC is in a low stage (e.g., 0-30%) or a high stage (e.g., 70% -100%), the SOC estimation accuracy is low, and the error between the estimated actual SOC and the actual SOC of the battery is large, and correction is required, therefore, a correction data table needs to be queried according to the actual measured current and the actual measured voltage, and SOC upper limit correction data and SOC lower limit correction data matched with the actual measured current and the actual measured voltage are obtained, so that correction is performed by using the SOC upper limit correction data and the SOC lower limit correction data.

The correction data table is a data table in which different configuration correction data are recorded in advance. The configuration correction data refers to data which is formed according to the battery operation condition before the system time for acquiring the measured data of the battery and is recorded in the memory of the BMS, and can be understood as data which is required to be called for estimating and correcting the measured SOC. Generally, configuring the correction data may be understood that, when the preset current and the preset voltage are satisfied, the corresponding actual SOC should be within an error range of the preset SOC, so as to correct the actual SOC, ensure that an error between the target SOC determined after correction and the actual SOC of the battery is small, and improve accuracy of the target SOC. For example, when the preset current is 1.2C, the configuration correction data with the preset current of 1.2C stored in the correction data table is as follows:

[5％，1.2C，V1，D1，C1]

[15％，1.2C，V2，D2，C2]

[25％，1.2C，V3，D3，C3]

[75％，1.2C，V4，D4，C4]

[85％，1.2C，V5，D5，C5]

[95％，1.2C，V6，D6，C6]

the SOC upper limit correction data is configuration correction data for correcting an upper limit of the actually measured SOC. The SOC lower limit correction data is arrangement correction data for correcting the lower limit of the actually measured SOC.

As an example, after receiving the measured data of the battery, the BMS queries a pre-stored correction data table based on the measured current and the measured voltage, selects a preset current to match the measured current, and determines configuration correction data in which the preset voltage matches the measured voltage as SOC upper limit correction data and SOC lower limit correction data. In this example, the BMS may select the configuration correction data, of which the preset voltage is closest to the measured voltage, from all the configuration correction data, of which the preset current matches the measured current and the preset voltage is greater than the measured voltage, to determine the configuration correction data as the SOC upper limit correction data; and selecting the configuration correction data with the preset voltage closest to the actual measurement voltage from all the configuration correction data with the preset current matched with the actual measurement current and the preset voltage smaller than the actual measurement voltage to determine the configuration correction data as SOC lower limit correction data.

S13: and determining an SOC upper limit threshold and an SOC lower limit threshold according to the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data.

The SOC upper limit threshold is an evaluation threshold for comparing and determining whether the upper limit of the actually measured SOC needs to be corrected. The SOC lower limit threshold is an evaluation threshold for comparing and determining whether or not the lower limit of the actually measured SOC needs to be corrected.

As an example, the BMS executes a threshold determination logic to process the SOC upper limit correction data and obtain an SOC upper limit threshold; and processing the SOC lower limit correction data to obtain an SOC lower limit threshold. Understandably, the SOC upper limit correction data and the SOC lower limit correction data both only comprise preset current and preset voltage, and also comprise preset SOC, a preset accumulated current error and preset accumulated historical electric quantity; the BMS can execute threshold value determination logic in real time, process the actually measured accumulated historical electric quantity and the preset SOC, the preset accumulated current error and the preset accumulated historical electric quantity in the SOC upper limit correction data, and determine an SOC upper limit threshold value; and executing threshold value determining logic in real time, processing the actually measured accumulated historical electric quantity and the preset SOC, the preset accumulated current error and the preset accumulated historical electric quantity in the SOC lower limit correction data, and determining the SOC lower limit threshold value. In this example, the threshold determination logic is a logic that uses the actually measured accumulated historical electric quantity, the preset SOC, the preset accumulated current error, and the preset accumulated historical electric quantity as input parameters and processes the input parameters by using a preset operation rule.

S14: and correcting the actual measurement SOC by adopting an SOC upper limit threshold and an SOC lower limit threshold to obtain the target SOC.

The target SOC is determined after the actually measured SOC is corrected by utilizing an SOC upper limit threshold and an SOC lower limit threshold, is the finally determined SOC, has the minimum error with the actual SOC of the battery and has the highest accuracy.

As an example, after determining the SOC upper threshold and the SOC lower threshold, the BMS may compare the measured SOC with the SOC upper threshold and the SOC lower threshold using a pre-configured SOC correction logic, to determine whether the measured SOC needs to be corrected according to a comparison result between the measured SOC and the SOC lower threshold and the SOC upper threshold, and to specifically implement how to correct the measured SOC when it is determined that the measured SOC needs to be corrected. For example, when the actual measured SOC is not between the lower SOC threshold and the upper SOC threshold, the SOC compensation rule may be used to compensate the actual measured SOC smaller than the lower SOC threshold, or compensate the actual measured SOC larger than the upper SOC threshold, so that the target SOC determined after compensation is closer to the range between the lower SOC threshold and the upper SOC threshold, thereby ensuring the minimum error between the target SOC and the actual SOC of the battery and the highest accuracy. The SOC compensation rule is a preset rule for compensating the actually measured SOC, different compensation conditions and compensation formulas corresponding to each compensation condition can be configured in the SOC compensation rule, so that the corresponding compensation conditions are determined according to actual conditions, and the corresponding compensation formulas are adopted for processing.

According to the battery SOC estimation method provided by the embodiment, the correction data table is inquired according to the actually measured current and the actually measured voltage, and the SOC upper limit correction data and the SOC lower limit correction data are quickly determined, so that the SOC estimation requires low resources and is beneficial to providing the real-time property of SOC estimation; and determining an SOC upper limit threshold and an SOC lower limit threshold based on the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data, and correcting the actually measured SOC by utilizing the SOC upper limit threshold and the SOC lower limit threshold for evaluation, so that the accuracy of the output target SOC is higher, the error between the output target SOC and the actual SOC of the battery is small, and the requirements of high accuracy, low resource requirement and high instantaneity can be considered for SOC estimation.

In one embodiment, the step S12, querying the correction data table according to the measured current and the measured voltage, and obtaining the SOC upper limit correction data and the SOC lower limit correction data matched with the measured current and the measured voltage, includes:

s121: and inquiring the correction data table based on the actually measured current to obtain SOC (system on chip) to-be-selected correction data of which the preset current is matched with the actually measured current in the correction data table.

S122: and acquiring SOC upper limit correction data and SOC lower limit correction data based on the actually measured voltage and the SOC candidate correction data.

The SOC candidate correction data refers to configuration correction data of which the preset current is matched with the actually measured current, namely all configuration correction data corresponding to the preset current matched with the actually measured current are determined as SOC candidate correction data. In this example, the preset current matched with the measured current may be a preset current equal to the measured current, or may be a preset current that is not equal to but closest to the measured current.

As an example, if the measured current of the battery data [ SOC0, 1.2C, V0, D0, C0] is 1.2C, the configuration correction data corresponding to all preset currents of 1.2C obtained from the correction data table are determined as SOC candidate correction data, for example, the SOC candidate correction data are as follows:

[5％，1.2C，V1，D1，C1]

[15％，1.2C，V2，D2，C2]

[25％，1.2C，V3，D3，C3]

[75％，1.2C，V4，D4，C4]

[85％，1.2C，V5，D5，C5]

[95％，1.2C，V6，D6，C6]

in the SOC candidate correction data, when the preset current is matched with the actually measured current, the preset voltage is in direct proportion to the preset SOC, that is, the larger the preset voltage is, the larger the preset SOC is.

Understandably, the preset voltage and the measured voltage in all the SOC to-be-selected correction data with the preset current matched with the measured current can be processed in an ascending or descending manner to form a voltage sequencing sequence, and the SOC to-be-selected correction data corresponding to two preset voltages adjacent to the measured voltage in the voltage sequencing sequence are respectively determined as SOC upper limit correction data and SOC lower limit correction data, so that the SOC upper limit correction data and the SOC lower limit correction data are used for correcting the upper limit or the lower limit of the measured SOC, the accuracy of the finally determined target SOC is ensured, and the error between the target SOC and the actual SOC of the battery is reduced.

In an embodiment, step S121, querying the correction data table based on the measured current, and obtaining SOC correction data to be selected, where the preset current in the correction data table matches the measured current, includes:

s1211: and if the preset current in the correction data table is equal to the actually measured current, taking the first correction data corresponding to the preset current as SOC (system on chip) correction data to be selected.

S1212: and if the preset current in the correction data table is not equal to the actually measured current, acquiring second correction data and third correction data in the correction data table, and acquiring SOC (system on chip) to-be-selected correction data based on the actually measured current, the second correction data and the third correction data, wherein the preset current in the second correction data is smaller than the actually measured current, and the preset current in the third correction data is larger than the actually measured current.

As an example, the measured current may be compared with the preset current in all the configuration correction data in the correction data table. And if the preset current is equal to the actually measured current, determining the configuration correction data of which the preset current is equal to the actually measured current as first correction data, wherein the first correction data are SOC (system on chip) to-be-selected correction data. And if the preset current is not equal to the measured current, sequencing the measured current and the preset current in all the configuration correction data to obtain a current sequencing sequence, and respectively determining two configuration correction data adjacent to the measured current as second correction data and third correction data. For example, the configuration correction data that the preset current is smaller than the measured current in two preset currents adjacent to the measured current in the current sorting sequence is determined as second correction data; and determining the configuration correction data of which the preset current is larger than the measured current in two preset currents adjacent to the measured current in the current sequencing sequence as third correction data.

In an embodiment, in step S1212, obtaining the SOC candidate correction data based on the measured current, the second correction data, and the third correction data, includes: and processing the measured current, the second correction data and the third correction data by adopting a data estimation formula to obtain SOC (state of charge) to-be-selected correction data.

The data estimation formula is ST ═ (Sa-Sb) × (IT-Ib)/(Ia-Ib) + Sb; if Sa is a preset voltage in the second correction data and Sb is a preset voltage in the third correction data, ST is a preset voltage in the SOC to-be-selected correction data; if Sa is the preset SOC in the second correction data and Sb is the preset SOC in the third correction data, ST is the preset SOC in the SOC to-be-selected correction data; if Sa is the preset accumulated historical electric quantity in the second correction data and Sb is the preset accumulated historical electric quantity in the third correction data, ST is the preset accumulated historical electric quantity in the SOC to-be-selected correction data; i is_TIs the measured current; ia is a preset current in the second correction data; ib is the predetermined current in the third correction data.

In this embodiment, the BMS may directly determine the measured current as the measured current, and after determining the second correction data and the third correction data, may process the measured current with specific values of the preset current, the preset voltage, the preset accumulated current error, the preset accumulated historical electric quantity, and the like in the second correction data and the third correction data to determine the SOC correction data to be selected.

As an example, the BMS processes the measured current, the second correction data and the third correction data by using a data estimation formula to obtain SOC correction data to be selected; wherein the data estimation formula is ST ═ (Sa-Sb) × (IT-Ib)/(Ia-Ib) + Sb; if Sa is the preset voltage in the second correction dataIf Sb is a preset voltage in the third correction data, ST is a preset voltage in the SOC correction data to be selected; if Sa is the preset SOC in the second correction data and Sb is the preset SOC in the third correction data, ST is the preset SOC in the SOC to-be-selected correction data; if Sa is the preset accumulated historical electric quantity in the second correction data and Sb is the preset accumulated historical electric quantity in the third correction data, ST is the preset accumulated historical electric quantity in the SOC to-be-selected correction data; i is_TIs the measured current; ia is a preset current in the second correction data; ib is the predetermined current in the third correction data.

For example, the second correction data [ SOCa, Ia, Va, Da, Ca]Is [ 75%, 1.3C, 3.458, 5AH, 30000AH]Third correction data [ SOCb, Ib, Vb, Db, Cb]Is [ 75%, 1.0C, 3.412, 6AH, 22000AH]Measured current I_TWhen 1.2C, the measured voltage estimation formula is V_T＝(Va-Vb)*

(I0-Ib)/(Ia-Ib) + Vb (3.458-3.412) × (1.2-1.0)/(1.3-1.0) +3.412 ═ 3.443, i.e. the measured voltage V_T3.443; the actual measurement accumulated current error formula is D_T(Da-Db) — (I0-Ib)/(Ia-Ib) + Db ═ (5-6) — (1.2-1.0)/(1.3-1.0) +6 ═ 5.33; actual measurement accumulated current error D_TIs 5.33. The formula of the actually measured accumulated historical electric quantity is C_T(Ca-Cb) (I0-Ib)/(Ia-Ib) + Cb ═ 30000-_T27333, the final measured data of the cell is [ 75%, 1.2C, 3.443, 5.33AH, 27333AH]。

Furthermore, the actually measured data of the battery also comprises an actually measured accumulated current error; correspondingly, the SOC candidate correction data also comprises a preset accumulated current error, and the second correction data and the third correction data also comprise the preset accumulated current error, and the BMS processes the actually measured current, the second correction data and the third correction data by adopting a data estimation formula to obtain the SOC candidate correction data; wherein the data estimation formula is ST ═ (Sa-Sb) × (IT-Ib)/(Ia-Ib) + Sb; if Sa is the preset accumulated current error in the second correction data and Sb is the preset accumulated current error in the third correction data, ST is the preset accumulated current error in the SOC correction data to be selected; i is_TIs the measured current; ia is a preset current in the second correction data; ib is the predetermined current in the third correction data.

The method for estimating the SOC of the battery according to the embodiment can quickly determine the SOC candidate correction data based on the measured current, the second correction data and the third correction data according to the measured current, the second correction data and the third correction data, so that the SOC estimation correction is performed by using the acquired SOC candidate correction data, the accuracy of the finally determined target SOC is guaranteed, and the error with the actual SOC is reduced.

In an embodiment, step S122, obtaining SOC upper limit correction data and SOC lower limit correction data based on the measured voltage and the SOC candidate correction data, includes:

s1221: and if the preset voltage in the SOC candidate correction data is larger than the actually measured voltage, determining the difference value between the preset voltage and the actually measured voltage in the SOC candidate correction data as a first difference value, and determining the SOC candidate correction data with the minimum first difference value as SOC upper limit correction data.

S1222: and if the preset voltage in the SOC candidate correction data is smaller than the actual measurement voltage, determining the difference value between the actual measurement voltage and the preset voltage in the SOC candidate correction data as a second difference value, and determining the SOC candidate correction data with the minimum second difference value as SOC lower limit correction data.

As an example, if the measured current of the battery data [ SOC0, 1.2C, V0, D0, C0] is 1.2C, the configuration correction data corresponding to all preset currents of 1.2C obtained from the correction data table is determined as SOC candidate correction data, for example, the SOC candidate correction data are as follows:

[5％，1.2C，V1，D1，C1]

[15％，1.2C，V2，D2，C2]

[25％，1.2C，V3，D3，C3]

[75％，1.2C，V4，D4，C4]

[85％，1.2C，V5，D5，C5]

[95％，1.2C，V6，D6，C6]

As an example, the measured voltage V0 is compared to preset voltages V1, V2, V3, V4, V5, and V6. If the preset voltages V5 and V6 are greater than the measured voltage V0, at the moment, the difference between the preset voltage V5 and the measured voltage V0 can be calculated and determined as a first difference V5-V0, and the difference between the preset voltage V6 and the measured voltage V0 is calculated and determined as a first difference V6-V0; and comparing the first difference values V5-V0 with V6-V0, wherein the first difference values V5-V0 are smaller than the first difference values V6-V0, so that SOC candidate correction data [ 85%, 1.2C, V5, D5 and C5] corresponding to the first difference values V5-V0 can be determined as SOC upper limit correction data. If the preset voltages V1, V2, V3 and V4 are all smaller than the measured voltage V0, second differences V0-V1, V0-V2, V0-V3 and V0-V4 between the measured voltage V0 and the preset voltages V1, V2, V3 and V4 are respectively calculated, and since V0-V4 are minimum, SOC candidate correction data [ 75%, 1.2C, V4, D4 and C4] corresponding to the second differences V0-V4 can be determined as SOC lower limit correction data.

In one embodiment, the step S13 of determining the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data, and the SOC lower limit correction data includes:

s131: and acquiring an upper limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC upper limit correction data, and determining the sum of the preset SOC and the upper limit error value in the SOC upper limit correction data as an SOC upper limit threshold.

S132: and acquiring a lower limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC lower limit correction data, and determining a difference value between a preset SOC in the SOC lower limit correction data and the lower limit error value as an SOC lower limit threshold.

As an example, the BMS first processes the preset accumulated current error and the preset accumulated historical electric quantity in the actually measured accumulated historical electric quantity and the SOC upper limit correction data by using an upper limit error value calculation formula, and obtains an upper limit error value, where the upper limit error value calculation formula is Wu ═ Du + k × (C)_T-Cu)，C_TFor actually measuring the accumulated historical electric quantity, Du and Cu are respectively a preset accumulated current error and a preset accumulated historical electric quantity in the SOC upper limit correction data, Wu is an upper limit error value, and k is an accumulated historical electric quantity attenuation coefficient. The accumulated historical electric quantity attenuation coefficient k can be obtained based on the battery cycle attenuation experimental data. For example, the data is corrected at the SOC upper limit [ 85%, 1.2C, V5, D5, C5]In the specification, Du is taken as D5, and Cu is taken as C5. Next, the BMS determines a sum of the preset SOCu and the upper-limit error value Wu in the SOC upper-limit correction data as an SOC upper-limit threshold to define an upper error limit corresponding to the preset SOCu, that is, an upper error limit acceptable to the preset SOCu.

As an example, the BMS first processes the preset accumulated current error and the preset accumulated historical electric quantity in the actually measured accumulated historical electric quantity and the SOC lower limit correction data using a lower limit error value calculation formula, to obtain a lower limit error value, where the lower limit error value calculation formula is Wp ═ Dp + k × (C)_T-Cp)，C_TFor actually measuring the accumulated historical electric quantity, Dp and Cp are respectively a preset accumulated current error and a preset accumulated historical electric quantity in the SOC lower limit correction data, Wp is a lower limit error value, and k is an accumulated historical electric quantity attenuation coefficient. The accumulated historical electric quantity attenuation coefficient k can be obtained based on the battery cycle attenuation experimental data. For example, the data is corrected at the SOC lower limit [ 75%, 1.2C, V4, D4, C4]In the specification, Dp is D4, and Cp is C4. Next, the BMS determines a sum of the preset SOCp and the lower-limit error value Wp in the SOC lower-limit correction data as an SOC lower-limit threshold to define a lower error limit corresponding to the preset SOCp, that is, a lower error limit acceptable for the preset SOCp.

In an embodiment, in step S14, the correcting the measured SOC by using the SOC upper threshold and the SOC lower threshold to obtain the target SOC includes:

s141: and if the actual measurement SOC is larger than the SOC upper limit threshold, determining the preset SOC in the SOC upper limit correction data as the target SOC.

S142: and if the actual measurement SOC is smaller than the SOC lower limit threshold, determining the preset SOC in the SOC lower limit correction data as the target SOC.

S143: and if the actual measurement SOC is not less than the SOC lower limit threshold value and the actual measurement SOC is not greater than the SOC upper limit threshold value, determining the actual measurement SOC as the target SOC.

As an example, if the measured SOC is greater than the SOC upper limit threshold, it indicates that the measured SOC is greater than the error upper limit acceptable by the preset SOCu in the SOC upper limit correction data, and at this time, the measured SOC is directly corrected to the preset SOCu in the SOC upper limit correction data, that is, the preset SOCu in the SOC upper limit correction data is directly determined as the target SOC, so as to avoid an excessive error between the target SOC and the actual SOC of the battery. For example, SOC Upper Limit correction data [ 85%, 1.2C, V5, D5, C5]The preset SOCu in (1) is 85%, the upper limit error value is 2%, the SOC upper limit threshold value is 87%, and if the actual SOC is measured_TAt 88%, the preset SOCu in the SOC upper limit correction data is determined as the target SOC, i.e., the target SOC is 85%.

As an example, if the measured SOC is smaller than the SOC lower limit threshold, it indicates that the measured SOC is smaller than the lower error limit acceptable by the preset SOCp in the SOC lower limit correction data, and at this time, the measured SOC is directly corrected to the preset SOCp in the SOC lower limit correction data, that is, the preset SOCp in the SOC lower limit correction data is directly determined as the target SOC, so as to avoid an excessive error between the target SOC and the actual SOC of the battery. For example, SOC lower limit correction data [ 75%, 1.2C, V4, D4, C4]The preset SOCp is 75%, the lower limit error value is 2%, the SOC lower limit threshold value is 73%, and the SOC is_TAt 71%, the preset SOCp in the SOC lower limit correction data is determined as the target SOC, and the target SOC is 75%.

As an example, if the measured SOC is not less than the SOC lower limit threshold and the measured SOC is not greater than the SOC upper limit threshold, it indicates that the measured SOC is not less than the lower error limit acceptable by the preset SOCp in the SOC lower limit correction data and the measured SOC is not greater than the upper error limit acceptable by the preset SOCu in the SOC upper limit correction data, the measured SOC is directly determined as the target SOC, which can ensure the accuracy of the target SOC and make the error between the measured SOC and the actual SOC of the battery smaller. For example, if the lower SOC threshold is 73% and the upper SOC threshold is 87%, if the measured SOC is 80% and 73% < 80% < 87%, the measured SOC is directly determined as the target SOC, that is, the target SOC is 80%, and no correction is necessary.

According to the battery SOC estimation method provided by the embodiment, a correction data table is inquired according to the actually measured current and the actually measured voltage in the actually measured data of the battery, and the SOC upper limit correction data and the SOC lower limit correction data are quickly determined from the limited configuration correction data, so that the SOC estimation requires low resources and is beneficial to providing the real-time property of SOC estimation; and determining an SOC upper limit threshold and an SOC lower limit threshold based on the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data, and correcting the actually measured SOC by utilizing the SOC upper limit threshold and the SOC lower limit threshold for evaluation, so that the accuracy of the output target SOC is higher, the error between the output target SOC and the actual SOC of the battery is small, and the requirements of high accuracy, low resource requirement and high instantaneity can be considered for SOC estimation.

In one embodiment, the measured battery data further includes a measured accumulated current error. As shown in fig. 2, after step S11, that is, after acquiring the measured battery data, the method for estimating the SOC of the battery further includes:

s21: and comparing the measured accumulated current error with the current error tolerance value.

S22: and if the actual measurement accumulated current error is larger than the current error tolerance value, inquiring a correction data table according to the actual measurement current and the actual measurement voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the actual measurement current and the actual measurement voltage.

S23: and if the actually measured accumulated current error is not larger than the current error tolerance value, updating the configuration correction data in the correction data table based on the actually measured data of the battery.

Further, the measured battery data further includes a measured accumulated current error. The actual measurement accumulated current error refers to the actual measurement number of the received batteryAccording to the accumulated electric quantity of all errors, D can be used_TIt is shown that, in general, the measured accumulated current error is counted again after each full or empty, and is the accumulation of all the error charges counted after the full or empty. It can be understood that the measured accumulated current error includes the sum of all error electric quantities before the system time and the accumulated error electric quantity formed by the measured data of the battery at this time. The error electric quantity here can be understood as an error between the measured SOC and the actual SOC of the battery.

The current error tolerance value is a pre-configured threshold value for evaluating whether the configuration correction data in the correction data table needs to be updated, and may be, for example, 2% of the battery level.

As an example, the BMS may compare the measured accumulated current error with a preset current error tolerance value; if the actual measurement accumulated current error is larger than the current error tolerance value, executing the steps S12-S14 to realize the correction processing of the actual measurement SOC and output the target SOC so as to ensure the accuracy of the target SOC; and if the actually measured accumulated current error is not greater than the current error tolerance value, updating the configuration correction data in the correction data table based on the actually measured battery data so as to update the configuration correction data in the correction data table according to the actual operation condition of the battery and ensure the accuracy and the real-time performance of the configuration correction data in the correction data table.

In this embodiment, in the actual operation process of the battery, the physical condition of the battery changes in real time, such as battery aging, reduction of total battery capacity, abnormal increase of internal resistance, and the like, so that the accuracy of SOC estimation of the battery with the physical condition change by the configuration correction data stored in the correction data table in the memory of the BMS when the battery leaves the factory is reduced, and when the actual measurement accumulated current error in the actual measurement data of the battery is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the actual measurement data of the battery, which is helpful for improving the accuracy of SOC estimation and correction of the subsequently acquired actual measurement data of the battery.

Since the current value can be evaluated as an index for reducing the maximum difference, the accumulated current error is an index for evaluating the deviation of the historical current from the preset current. The accumulated historical electric quantity is equivalent to the recorded time validity, and the unreliability of the battery is increased along with the increase of the electric quantity of the battery; therefore, the unreliability calculation of different preset currents in all configuration correction data with the same preset SOC and the same actual SOC can be carried out based on the actual measured current, the actual measured accumulated current error and the actual measured accumulated historical electric quantity in the actual measured data of the battery, the actual measured unreliable value of the actual measured data of the battery is obtained, and whether the configuration correction data in the correction data table needs to be updated by the actual measured data of the battery is determined according to the actual measured unreliable value.

In one embodiment, the measured battery data includes measured SOC, measured current, measured voltage, measured accumulated current error, and measured accumulated historical charge, and SOC can be used_T、I_T、V_T、D_T、C_T]Represents; the configuration correction data includes preset current, preset voltage, preset SOC, preset accumulated current error and preset accumulated historical electric quantity, and [ SOCn, In, Vn, Dn, Cn]And (4) showing. Step S23, updating the configuration correction data in the correction data table based on the battery measured data, includes:

s231: acquiring SOC initial selection correction data of which all preset SOCs are matched with the actually measured SOCs in the correction data table, determining the SOC initial selection correction data of which the preset current is adjacent to the actually measured current as first to-be-updated correction data and second to-be-updated correction data, determining the first to-be-updated correction data and the second to-be-updated correction data as SOC to-be-updated correction data, wherein the preset current in the first to-be-updated correction data is smaller than the actually measured current, and the preset current in the second to-be-updated correction data is larger than the actually measured current.

S232: and processing the actually measured data of the battery and the corrected data to be updated of the SOC to obtain an actually measured unreliable value corresponding to the actually measured data of the battery and an unreliable value to be updated corresponding to the corrected data to be updated of the SOC.

S233: and if the actual measurement unreliable value is smaller than the unreliable value to be updated, updating the corrected data to be updated of the SOC by adopting the actual measurement data of the battery.

As an example, step S231 specifically includes: (1) and comparing the preset SOC in all the configuration correction data in the correction data table, and determining the configuration correction data of which the preset SOC is matched with the actually-measured SOC as SOC initial selection correction data. For example, the arrangement correction data in which the preset SOC is equal to the actual measurement SOC is determined as the SOC initial selection correction data, or the arrangement correction data in which the preset SOC is closest to the actual measurement SOC is determined as the SOC initial selection correction data. (2) And determining the SOC initial selection correction data adjacent to the preset current and the measured current as SOC screening correction data. For example, the preset currents and the measured currents in all the SOC initial selection correction data are sorted to form a current sorting sequence, the SOC initial selection correction data corresponding to two preset currents adjacent to the measured currents in the current sorting sequence, that is, the SOC initial selection correction data corresponding to two preset currents before and after the measured currents in the current sorting sequence are respectively determined as first to-be-updated correction data and second to-be-updated correction data, and the first to-be-updated correction data and the second to-be-updated correction data are determined as SOC screening correction data, so that whether the to-be-updated SOC correction data needs to be updated or not is determined according to the battery measured data and the SOC to-be-updated correction data, and the accuracy of a subsequent battery SOC estimation algorithm is guaranteed. The SOC initial selection correction data corresponding to the preset current with the minimum difference value from all the preset currents smaller than the actual measurement current is the first to-be-updated correction data. And the SOC primarily selected correction data corresponding to the preset current with the minimum difference value with the actually measured current in the preset current larger than the actually measured current in the second correction data to be updated is the second correction data to be updated.

As an example, step S232 specifically includes: processing the actually measured battery data by adopting an unreliable value formula to obtain an actually measured unreliable value corresponding to the actually measured battery data; processing the SOC to-be-updated correction data by adopting an unreliable value formula, and acquiring the unreliable value to be updated corresponding to the SOC to-be-updated correction data, wherein the unreliable value formula is Q (CTBm) ═ ABS (Io-CTBm) < f + Do < g + (C)_T-Co) h, Q (CTBm) is an unreliable value corresponding to the preset current CTBm, which is an actually measured unreliable value or is not to be updatedA reliable value; ABS is an absolute value function; io is the current used for calculating the unreliable value, and is the measured current I_TOr a preset current In; f is the current coefficient; do is the accumulated current error used to calculate the unreliable value, which may be the measured accumulated current error D_TOr a preset accumulated current error Dn; g is an accumulated current error coefficient; co is the accumulated historical electric quantity used for calculating the unreliable value, and can be the actually measured accumulated historical electric quantity C_TOr preset accumulated historical electric quantity Cn; h is the accumulated historical electric quantity coefficient. Understandably, f, g, and h may be determined autonomously by the user based on experience.

In an embodiment, step S232, processing the actually measured data of the battery and the corrected data to be updated of the SOC to obtain an actually measured unreliable value corresponding to the actually measured data of the battery and an unreliable value to be updated corresponding to the corrected data to be updated of the SOC, includes:

s2321: using formula Q of actually measured unreliable values_T(CTBm)＝ABS(I_T-CTBm)*f+D_T*g+(C_T-C_T) And calculating the actually measured data of the battery by h, and acquiring an actually measured unreliable value corresponding to the actually measured data of the battery.

S2322: adopting the formula Qn (CTBm) ═ ABS (In-CTBm) × f + Dn × g + (C) to be updated_Tand-Cn) h, calculating the corrected data to be updated of the SOC and the actually measured data of the battery, and acquiring unreliable values to be updated corresponding to the corrected data to be updated of the SOC.

Wherein Q is_T(CTBm) is an actually measured unreliable value corresponding to the actually measured data of the battery; CTBm is a preset current; ABS is an absolute value function; i is_T、D_TAnd C_TRespectively measuring the current, the error of the accumulated current and the historical electric quantity in the measured data of the battery; qn (CTBm) is an unreliable value to be updated corresponding to the correction data to be updated of the SOC; in, Dn and Cn are respectively a preset current, a preset accumulated current error and a preset accumulated historical electric quantity corresponding to the corrected data to be updated of the SOC; f is the current coefficient; g is an accumulated current error coefficient; h is the accumulated historical electric quantity coefficient.

The following illustrates a procedure of performing update processing on configuration correction data:

(1) assuming that the predetermined SOC is 75%, the predetermined current CTB1 is 0.2, CTB2 is 0.7, CTB3 is 1.2, CTB4 is 1.7, and CTB5 is 2.2, f is 1000, g is 10, and h is 0.01, for example, the coefficient is not exactly the actual usage coefficient, and the coefficient can be adjusted according to the battery and the conditions of the project. In the initial state, 5 pieces of configuration correction data are acquired as follows:

CTB1 ═ 0.2C: empty;

CTB2 ═ 0.7C: empty;

CTB3 ═ 1.2C: empty;

CTB4 ═ 1.7C: empty;

CTB5 ═ 2.2C: empty;

(2) when the measured SOC reaches 75 and the measured accumulated current error is not greater than the current error tolerance (e.g., 2%), acquiring 1 st battery measured data [ 75%, 1.0C, 3.356, 3AH, 28000AH ], wherein the configuration correction data corresponding to CTB2 and CTB3 is SOC to-be-updated correction data because CTB2<1.0C < CTB3, wherein the configuration correction data corresponding to CTB2 is the first to-be-updated correction data, and the configuration correction data corresponding to CTB3 is the second to-be-updated correction data, and since the two SOC to-be-updated correction data are empty in the initial state (1), the SOC to-be-updated correction data can be directly updated by using the battery measured data, and 5 configuration correction data are acquired as follows:

CTB1 ═ 0.2C: empty;

CTB2＝0.7C：[75％，1.0C，3.412，6AH，22000AH]；

CTB3＝1.2C：[75％，1.0C，3.412，6AH，22000AH]；

CTB4 ═ 1.7C: empty;

CTB5 ═ 2.2C: empty;

(3) when the measured SOC reaches 75% and the measured accumulated current error is not greater than the current error tolerance (e.g. 2%), acquiring the 2 nd measured battery data [ 75%, 0.3C, 3.356, 3AH, 28000AH ], wherein the configuration correction data corresponding to CTB1 and CTB2 is the SOC to-be-updated correction data because CTB1<0.3C < CTB2, wherein the configuration correction data corresponding to CTB1 is the first to-be-updated correction data, the configuration correction data corresponding to CTB2 is the second to-be-updated correction data, and according to the formula of the unreliable values, the to-be-updated unreliable values corresponding to the SOC to-be-updated correction data and the measured unreliable values corresponding to the measured battery data are respectively acquired as follows:

the unreliable values to be updated corresponding to the corrected data to be updated of the SOC are as follows:

CTB1 ═ 0.2C: empty;

qn (CTB1) is null;

CTB2＝0.7C：[75％，1.0C，3.412，6AH，22000AH]；

Qn(CTB2)＝(1.0–0.7)*1000+6*10+(28000–22000)*0.01＝420；

the actual measurement unreliable values corresponding to the actual measurement data of the battery are as follows:

CTB1＝0.2C：[75％，0.3C，3.356，3AH，28000AH]；

Q_T(CTB1)＝(0.3–0.2)*1000+3*10+(28000–28000)*0.01＝130；

CTB2＝0.7C：[75％，0.3C，3.356，3AH，28000AH]；

Q_T(CTB2)＝(0.7–0.3)*1000+3*10+(28000–28000)*0.01＝430；

since Qn (CTB1) is empty, Q_T(CTB1) 130, which needs to be updated; because Qn (CTB2) is 420<Q_T(CTB2) — 430, no row update is needed, and the 5 configuration correction data updated are as follows:

CTB1＝0.2C：[75％，0.3C，3.356，3AH，28000AH]；

CTB2＝0.7C：[75％，1.0C，3.412，6AH，22000AH]；

CTB3＝1.2C：[75％，1.0C，3.412，6AH，22000AH]；

CTB4 ═ 1.7C: empty;

CTB5 ═ 2.2C: empty;

(4) when the actual measurement SOC reaches 75% and the actual measurement accumulated current error is not greater than the current error tolerance (e.g. 2%), acquiring the 3 rd battery actual measurement data [ 75%, 1.3C, 3.458, 5AH, 30000AH ], since CTB3<1.3C < CTB4, the configuration correction data corresponding to CTB3 and CTB4 are the SOC correction data to be updated, wherein the configuration correction data corresponding to CTB3 is the first correction data to be updated, the configuration correction data corresponding to CTB4 is the second correction data to be updated, and according to the formula of the unreliable values, the unreliable values to be updated corresponding to the SOC correction data to be updated and the actual measurement unreliable values corresponding to the battery actual measurement data are respectively acquired as follows:

CTB3＝1.2C：[75％，1.0C，3.412，6AH，22000AH]；

Qn(CTB3)＝(1.2–1.0)*1000+6*10+(30000–22000)*0.01＝340；

CTB4 ═ 1.7C: air conditioner

Qn (CTB4) is null;

CTB3＝1.2C：[75％，1.3C，3.458，5AH，30000AH]；

Q_T(CTB3)＝(1.3–1.2)*1000+5*10+(30000–30000)*0.01＝150；

CTB4＝1.7C：[75％，1.3C，3.458，5AH，30000AH]；

Q_T(CTB4)＝(1.7–1.3)*1000+5*10+(30000–30000)*0.01＝450；

because Qn (CTB3) is 340>Q_T(CTB3) — 150, an update is required; since Qn (CTB4) is empty, Q_TIf the (CTB4) needs to be updated when it is 450, the 5 updated configuration correction data are as follows:

CTB1＝0.2C：[75％，0.3C，3.356，3AH，28000AH]；

CTB2＝0.7C：[75％，1.0C，3.412，6AH，22000AH]；

CTB3＝1.2C：[75％，1.3C，3.458，5AH，30000AH]；

CTB4＝1.7C：[75％，1.3C，3.458，5AH，30000AH]；

CTB5 ═ 2.2C: empty;

(5) when the measured SOC reaches 75% and the measured accumulated current error is not greater than the current error tolerance (e.g. 2%), acquiring the 4 th battery measured data [ 75%, 1.9C, 3.485, 4AH, 35000AH ], wherein the configuration correction data corresponding to CTB4 and CTB5 is the SOC correction data to be updated, because CTB4<1.9C < CTB5, the configuration correction data corresponding to CTB4 is the first correction data to be updated, the configuration correction data corresponding to CTB5 is the second correction data to be updated, and according to the formula of the unreliable values, the unreliable values to be updated corresponding to the correction data to be updated of the SOC and the measured unreliable values corresponding to the battery measured data are respectively acquired as follows:

CTB4＝1.7C：[75％，1.3C，3.458，5AH，30000AH]；

Qn(CTB4)＝(1.7–1.3)*1000+5*10+(30000–22000)*0.01＝530；

CTB5 ═ 2.2C: empty;

qn (CTB4) is null;

CTB4＝1.7C：[75％，1.9C，3.485，4AH，35000AH]；

Q_T(CTB4)＝(1.9–1.7)*1000+4*10+(35000–35000)*0.01＝240

CTB5＝2.2C：[75％，1.9C，3.485，4AH，35000AH]；

Q_T(CTB5)＝(2.2–1.9)*1000+4*10+(35000–35000)*0.01＝340

since Qn (CTB4) is 530>Q_T(CTB4) — 240, needs to be updated; since Qn (CTB5) is empty, Q_T(CTB5) — 340, and needs to be updated, the 5 configuration correction data that are updated are as follows:

CTB1＝0.2C：[75％，0.3C，3.356，3AH，28000AH]；

CTB2＝0.7C：[75％，1.0C，3.412，6AH，22000AH]；

CTB3＝1.2C：[75％，1.3C，3.458，5AH，30000AH]；

CTB4＝1.7C：[75％，1.9C，3.485，4AH，35000AH]；

CTB5＝2.2C：[75％，1.9C，3.485，4AH，35000AH]；

by analogy, when the actual measurement SOC reaches the preset SOC and the actual measurement accumulated current error is not greater than the current error tolerance value, the BMS calculates and obtains an actual measurement unreliable value corresponding to the actual measurement data of the battery by using the actual measurement current, the actual measurement accumulated current error and the actual measurement accumulated historical electric quantity in the actual measurement data of the battery; and calculating the corresponding unreliable value to be updated by using the SOC to-be-updated correction data with the same preset SOC as the actually-measured SOC, namely acquiring the unreliable value to be updated corresponding to the SOC to-be-updated correction data by using a preset accumulated current error and a preset accumulated historical electric quantity in the SOC to-be-updated correction data, updating the SOC to-be-updated correction data by using battery actually-measured data corresponding to the actually-measured unreliable value smaller than the unreliable value to be updated so as to realize real-time updating of the configuration correction data in the correction data table, ensure the reliability of subsequent SOC estimation, and avoid the problem that the configuration correction data prestored in the correction data table can not accurately correct the actually-measured SOC when the physical condition of the battery changes.

For example, in the first execution of steps S11-S14, during the processing of the battery measured data corresponding to the measured current of 1.2C, the two configuration correction data of [ 75%, 1.0C, a, B, C ] and [ 75%, 1.3C, E, F, G ] stored in advance in the correction data table are used to determine the SOC upper limit correction data and the SOC lower limit correction data, respectively, so as to determine the final target SOC. After updating [ 75%, 1.0C, a, B, C ] to [ 75%, 0.9C, a ', B', C '] and subsequently performing steps S11-S14 again, it is necessary to employ two configuration correction data of [ 75%, 0.9C, a', B ', C' ] and [ 75%, 1.3C, E, F, G ] as the SOC upper limit correction data and the SOC lower limit correction data, respectively, in order to determine the final target SOC.

In an embodiment, before step S11 is executed, the correction data table needs to be determined in advance, specifically, the preset SOC and the preset current in the correction data table need to be determined through experiments, so that the actual operating condition of the battery can be subsequently updated and obtained in real time according to the actual operating condition of the battery, and the actual voltage, the actual accumulated current error and the actual accumulated historical electric quantity corresponding to the preset SOC and the preset current.

In one embodiment, a battery management system is provided, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the method for estimating the battery SOC is implemented in the above embodiments, for example, S11-S14 shown in fig. 1 or S21-S23 shown in fig. 2, which is not described herein again to avoid repetition.

In an embodiment, a computer-readable storage medium is provided, and a computer program is stored on the computer-readable storage medium, and when being executed by a processor, the computer program implements the method for estimating the SOC of the battery in the foregoing embodiments, for example, as shown in S11-S14 shown in fig. 1 or S21-S23 shown in fig. 2, and therefore, for avoiding repetition, details are not repeated here.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware related to instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the embodiments provided herein may include non-volatile and/or volatile memory, among others. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), synchronous Link (Synchlink) DRAM (SLDRAM), Rambus (Rambus) direct RAM (RDRAM), direct bused dynamic RAM (DRDRAM), and bused dynamic RAM (RDRAM).

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules, so as to perform all or part of the functions described above.

It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.

Claims

1. A battery SOC estimation method, characterized by comprising:

2. The battery SOC estimation method according to claim 1, wherein said retrieving correction data tables based on the measured current and the measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data that match the measured current and the measured voltage comprises:

inquiring a correction data table based on the measured current, and acquiring SOC (system on chip) to-be-selected correction data of which the preset current is matched with the measured current in the correction data table;

3. The battery SOC estimation method according to claim 2, wherein the querying a correction data table based on the measured current to obtain SOC candidate correction data in which a preset current in the correction data table matches the measured current includes:

4. The battery SOC estimation method according to claim 3, wherein said obtaining SOC candidate correction data based on the measured current, the second correction data, and the third correction data, comprises:

processing the actually measured current, the second correction data and the third correction data by adopting a data estimation formula to obtain SOC correction data to be selected;

the data estimation formula is ST ═ (Sa-Sb) × (IT-Ib)/(Ia-Ib) + Sb; if Sa is a preset voltage in the second correction data and Sb is a preset voltage in the third correction data, ST is a preset voltage in the SOC correction data to be selected; if Sa is a preset SOC in the second correction data and Sb is a preset SOC in the third correction data, ST is a preset SOC in the SOC to-be-selected correction data; if Sa is preset accumulated historical electric quantity in the second correction data and Sb is preset accumulated historical electric quantity in the third correction data, ST is preset accumulated historical electric quantity in the SOC to-be-selected correction data; i is_TIs the measured current; ia is a preset current in the second correction data; ib is the predetermined current in the third correction data.

5. The battery SOC estimation method according to claim 2, wherein the acquiring the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC candidate correction data includes:

6. The battery SOC estimation method of claim 1, wherein the determining an SOC upper limit threshold value and an SOC lower limit threshold value based on the measured accumulated historical electric quantity, the SOC upper limit correction data, and the SOC lower limit correction data includes:

7. The battery SOC estimation method according to claim 1, wherein the correcting the measured SOC using the SOC upper threshold and the SOC lower threshold to obtain a target SOC comprises:

8. The battery SOC estimation method of claim 1, wherein the battery measured data further includes a measured accumulated current error;

9. The battery SOC estimation method according to claim 8, wherein the updating of the configuration correction data in the correction data table based on the battery measured data includes:

acquiring SOC initial selection correction data of which all the preset SOCs are matched with the actually measured SOCs in the correction data table, determining the SOC initial selection correction data of which the preset current is adjacent to the actually measured current as first to-be-updated correction data and second to-be-updated correction data, and determining the first to-be-updated correction data and the second to-be-updated correction data as SOC to-be-updated correction data, wherein the preset current in the first to-be-updated correction data is smaller than the actually measured current, and the preset current in the second to-be-updated correction data is larger than the actually measured current;

10. The method for estimating SOC of a battery as claimed in claim 9, wherein the processing the measured battery data and the corrected SOC data to be updated to obtain the unreliable measured value corresponding to the measured battery data and the unreliable updated value corresponding to the corrected SOC data to be updated includes:

using formula Q of actually measured unreliable values_T(CTBm)＝ABS(I_T-CTBm)*f+D_T*g+(C_T-C_T) Calculating the actually measured data of the battery by h to obtain actually measured unreliable values corresponding to the actually measured data of the battery;

adopting the formula Qn (CTBm) ═ ABS (In-CTBm) × f + Dn × g + (C) to be updated_T-Cn) × h calculates the SOC correction data to be updated and the battery measured data, and obtains an unreliable value to be updated corresponding to the SOC correction data to be updated;

wherein Q is_T(CTBm) is an actually measured unreliable value corresponding to the actually measured data of the battery; CTBm is a preset current; ABS is an absolute value function; i is_T、D_TAnd C_TRespectively obtaining the measured current, the measured accumulated current error and the measured accumulated historical electric quantity in the measured data of the battery; qn (CTBm) is an unreliable value to be updated corresponding to the correction data to be updated of the SOC; in, Dn and Cn are respectively a preset current, a preset accumulated current error and a preset accumulated historical electric quantity corresponding to the corrected data to be updated of the SOC; f is the current coefficient; g is an accumulated current error coefficient; h is the accumulated historical electric quantity coefficient.

11. A battery management system comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the battery SOC estimation method according to any one of claims 1 to 10 when executing the computer program.

12. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the battery SOC estimation method according to any one of claims 1 to 10.